1. Field of the Invention
A system for fixing a rail onto a foundation, which includes a guide plate which guides the rail to be fixed on its long side, a spring element which can be clamped against a foundation by means of a clamping element and which sits on the guide plate and when the system is finally mounted, with a free spring arm exerts a retaining force on a rail foot of the rail to be fixed, and has a support plate which extends transverse to the rail to be fixed over the width of the guide plate and which is arranged to compensate for height differences between the guide plate and the foundation, wherein the support plate has a rectangular base form and includes a passage opening for the clamping element used to clamp the spring element. A support plate for such a system is also disclosed.
2. Description of Related Art
Such supports are used firstly to support other components of the fixing system to the foundation over a large area. Secondly it is used for height adjustment when the height level of the respective mounting surface of the foundation between two adjacent fixing points deviates beyond a tolerance range. If an unacceptable height deviation is found, it can be compensated by two or more support plates of different thickness being pushed below the rail concerned. In principle the requirement for subsequently inserting or changing the support plates is problematic here.
To eliminate this problem, DE 197 45 326 A1 discloses a support plate for a rail fixing system of the type described initially in which at least one of two diagonally opposed openings for the passage of clamping elements to be screwed into the foundation for clamping the spring element concerned are formed as a slot open towards the long side of the support plate. Even if it is possible in this way to push the support plate subsequently under the other components of a rail fixing system without having to completely release the clamping element, this design of a support plate in practice has the disadvantage that it must be very long to receive the slots necessary for the clamping element concerned. This applies in particular if the passage openings for the clamping elements, in contrast to the provision with the known support plate, are arranged centrally in relation to the longitudinal axis of the support plate. The layer of the fixing system above is not supported in the area of the large slot, with the consequence that the material of the layer concerned—irrespective of its properties—presses into the slot under the heavy loads occurring when a rail vehicle travels over the rails. This can lead to premature wear on the layer concerned or the support plate in the area of the slot. This danger is particularly critical if the rail is supported flexibly via an elastic layer lying on the support plate.